Nanofluidic point-of-care IgE test for subtropical grass pollen for rapid diagnosis of allergic rhinitis.

BACKGROUND: Widening of subtropical climate zones globally and increasing grass pollen exposure, provide impetus for development of more precise and accessible diagnosis of allergy.

OBJECTIVE: We evaluate the utility of recombinant allergen components of Panicoideae and Chloridoideae pollens for specific IgE testing in a rapid, point of care device.

METHODS: Recombinant (r) Pas n 1 and Cyn d 1 were expressed, purified, and tested in the nanofluidic device for measurement of serum specific IgE (spIgE) in a well-characterised Australian cohort. Concentrations and classes of spIgE to rPas n 1 and rCyn d 1, and total IgE were compared with skin prick test and spIgE to grass pollen.

RESULTS: Correlation between commercial and academic laboratories for 21 sera were with rPas n 1 spIgE (r=0.695) and total IgE (r=0.945). Higher spIgE to rPas n 1 and rCyn d 1 fluorescence were detected in the grass-pollen allergic patients with clinician diagnosed allergic rhinitis (n=134) than participants with other allergies (n=49) or no allergies (n=23). Correlation between spIgE concentrations to rPas n 1 (r=0.679) and rCyn d 1 (r=0.548), with Bahia and Bermuda grass pollen spIgE respectively, were highly significant (p<0.0001). The positive/negative predictive agreements of spIgE classes for rPas n 1 (73%/82.5%) and rCyn d 1 (67.8%/66.3%) between the nanofluidic and ImmunoCAP measurements for Bahia and Bermuda grass pollen, respectively were substantial.

CONCLUSION: Point of care nanofluidic tests for spIgE to rPas n 1 and rCyn d 1, could increase access to more precise clinical diagnosis for allergy patients in subtropical regions.